Hydrochloric Acid → Methyl 4-amino-2,5-dimethylthiophene-3-carboxylate

HRID 1577429Notes

Reaction equation

HRID 1577429 reaction equation
O[N:2]=[C:3]1[CH:7]([CH3:8])[S:6][CH:5]([CH3:9])[CH:4]1[C:10]([O:12][CH3:13])=[O:11].Cl>C(OCC)C>[NH2:2][C:3]1[C:4]([C:10]([O:12][CH3:13])=[O:11])=[C:5]([CH3:9])[S:6][C:7]=1[CH3:8]

Participants

4

Reactant 2

HCID 313Hydrochloric AcidHCID 86737305HCID 86737305, compound

Product 1

HCID 11019562Methyl 4-amino-2,5-dimethylthiophene-3-carboxylateYield 47.1%

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent

Procedure

A cooled solution of 80 g (0.39 mol) of tetrahydro-4-(hydroxyimino)-2,5-dimethyl-3-thiophenecarboxylic acid, methyl ester (Example D) in 1 L of anhydrous diethyl ether is saturated with dry hydrogen chloride over a period of one hour. The solution is stirred and allowed to reach room temperature over fourteen hours. The resulting precipitate is filtered, dissolved in 200 ml of water, neutralized with concentrated ammonium hydroxide and the aqueous solution is extracted with 200 ml of diethyl ether. The diethyl ether solution is washed with 100 ml of water. The diethyl ether layer is separated, dried over anhydrous Na2SO4 and evaporated to give 34 g of 4-amino-2,5-dimethyl-3-thiophenecarboxylic acid, methyl ester; mp 75°-77° C. after recrystallization from hexane.

Workup

  1. waitto reach room temperature over fourteen hours
  2. filtrationThe resulting precipitate is filtered
  3. dissolutiondissolved in 200 ml of water, neutralized with concentrated ammonium hydroxide
  4. extractionthe aqueous solution is extracted with 200 ml of diethyl ether
  5. washThe diethyl ether solution is washed with 100 ml of water
  6. customThe diethyl ether layer is separated
  7. dry with materialdried over anhydrous Na2SO4
  8. customevaporated

Sources & evidence

ORD record
ord-a60f77e84e6e4641907b157b925206e8
Source dataset
uspto-grants-1981_09
Patent number
US04287340

Reaction notes

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